varying vec4 v_fragmentColor;     
varying vec2 v_texCoord;      
          
void main()           
{  
    vec4 v_orColor = v_fragmentColor * texture2D(CC_Texture0, v_texCoord);  
    float gray = dot(v_orColor.rgb, vec3(0.299, 0.587, 0.114));  
    gl_FragColor = vec4(gray, gray, gray, v_orColor.a);  
} 